Technical Abstract:
Genetic diversity in reproductive abiotic stress tolerance has been investigated by cotton breeders throughout the public and private sectors. The primary focus of these studies has been the evaluation of abiotic stress responses during the development of the flower prior to anthesis. Sterility indices based upon the percentage of anther dehiscence are commonly used as a measure of mature pollen availability in adverse environments. An underlying assumption in these studies has been that the mature pollen released from the anthers is essentially equal among varieties, and that reproductive success is primarily associated with mature pollen availability. We have investigated mature pollen characteristics and have identified distinct genetic variability in the abiotic stress tolerance of the mature pollen. We have developed laboratory-based tests permitting rapid evaluation of the overall abiotic stress tolerance of the pollen. Our findings provide breeders with a previously unexplored reservoir of genetic diversity associated with reproductive abiotic stress tolerance.